Dispersive Evolution of Nonlinear Fast Magnetoacoustic Wave Trains

Pascoe, D. J.; Goddard, Christopher R.; Nakariakov, V. M.

doi:10.3847/2041-8213/aa8db8

Cited by 21 publications

(30 citation statements)

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“…This dependence on the driver duration is extremely important in attempts to unlock the seismological potential of these waves. Varying other parameters such as the spatial scale of the driver, and the transverse density profile of the waveguide can have similar effects on the final wave train signature (e.g., Nakariakov et al 2005;Pascoe et al 2013Pascoe et al , 2017Yu et al 2017). Therefore an effort to clearly distinguish these factors in both theoretical and observational studies should be made.…”

Section: Discussionmentioning

confidence: 99%

“…The numerical setup is similar to previous studies which have used the 2D slab geometry (e.g., Nakariakov et al 2004;Pascoe et al 2017). The magnetic field is straight and uniform in the z-direction, with strength B 0 .…”

Section: Modelmentioning

confidence: 99%

“…Since then wavelet analysis has been frequently used to visualise the obtained wave train signatures in both observational and numerical studies. Further theoretical studies have focused on different perpendicular density profiles of the waveguide (e.g., Yu et al 2017;Li et al 2018b), wave train formation in current sheets (e.g., Jelínek & Karlický 2012;Mészárosová et al 2014), accounting for 2D and cylindrical effects (Pascoe et al 2013;Shestov et al 2015), amplitudes entering the non-linear regime (Pascoe et al 2017), and analytical estimations (e.g., Oliver et al 2015).…”

Section: Introductionmentioning

confidence: 99%

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Fast magnetoacoustic wave trains with time-dependent drivers

Goddard

Nakariakov

Pascoe

2019

A&A

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Context. Frequent observations of quasi-periodic rapidly-propagating wave trains in coronal structures have been made in the last decade. The dispersive evolution of fast magnetohydrodynamic waves propagating in coronal waveguides can provide a physical interpretation for many of these observations. Aims. Previous studies have considered the generation of fast wave trains by impulsive drivers which deposit energy instantaneously. The signatures of dispersively formed wave trains must depend on the temporal nature of the driver. We investigate the effect of varying the temporal width of the driving perturbation. Methods. 2D magnetohydrodynamic numerical simulations of impulsively generated wave trains in a guiding field-aligned density enhancement were performed with the novel addition of a time-dependant driver. Results. The final spatial and spectral signatures of the guided wave trains are found to depend strongly on the temporal duration of the initial perturbation. In particular, the wavelength (or frequency) of highest spectral amplitude is found to increase (decrease) with increasing temporal duration, whereas the spectral width decreases. Additionally, the efficiency of generation of fast wave trains is found to decrease strongly with increasing temporal width of the driver, with a cut-off at twice the internal Alfvén crossing time.

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Section: Discussionmentioning

confidence: 99%

Section: Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Fast magnetoacoustic wave trains with time-dependent drivers

Goddard

Nakariakov

Pascoe

2019

A&A

Self Cite

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“…We need to stress that specific shapes of the transverse density profile of coronal MHD waveguides, for example, a coronal loop, polar plume, jet, streamer, etc., are not known, but are subject to intensive investigation (see, e.g., Aschwanden & Nightingale 2005;Brooks et al 2013;Arregui et al 2015;Pascoe et al 2017a;Goddard et al 2017Goddard et al , 2018Pascoe et al 2018, for coronal loops). In particular, Pascoe et al (2017b) demonstrated that the accumulation of nonlinear effects in the dynamics of the fast wave trains trapped in coronal plasma slabs is highly inhibited by strong waveguide dispersion, so that even for the relative perturbation amplitudes of several tens of percent the nonlinear steepening of the wave does not occur. The latter result clearly justifies the applicability of the linear MHD theory to modelling fast wave trains in coronal plasma structures.…”

Section: Introductionmentioning

confidence: 99%

Fast magnetoacoustic wave trains: from tadpoles to boomerangs

Kolotkov

Nakariakov

Moss

et al. 2021

Monthly Notices of the Royal Astronomical Society

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Rapidly propagating fast magnetoacoustic wave trains guided by field-aligned plasma non-uniformities are confidently observed in the Sun’s corona. Observations at large heights suggest that fast wave trains can travel long distances from the excitation locations. We study characteristic time signatures of fully developed, dispersive fast magnetoacoustic wave trains in field-aligned zero-β plasma slabs in the linear regime. Fast wave trains are excited by a spatially localised impulsive driver and propagate along the waveguide as prescribed by the waveguide-caused dispersion. In slabs with steeper transverse density profiles, developed wave trains are shown to consist of three distinct phases: a long-period quasi-periodic phase with the oscillation period shortening with time, a multi-periodic (peloton) phase in which distinctly different periods co-exist, and a short-lived periodic Airy phase. The appearance of these phases is attributed to a non-monotonic dependence of the fast wave group speed on the parallel wavenumber due to the waveguide dispersion, and is shown to be different for axisymmetric (sausage) and non-axisymmetric (kink) modes. In wavelet analysis, this corresponds to the transition from the previously known tadpole shape to a new boomerang shape of the wave train spectrum, with two well-pronounced arms at shorter and longer periods. We describe a specific previously published radio observation of a coronal fast wave train, highly suggestive of a change of the wavelet spectrum from a tadpole to a boomerang, broadly consistent with our modelling. The applicability of these boomerang-shaped fast wave trains for probing the transverse structuring of the waveguiding coronal plasma is discussed.

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“…Magnetohydrodynamic (MHD) waves carry the vital information of the source region, they propagate across structured waveguides, therefore, the analysis of MHD waves could be used to infer the key parameters of both the source and waveguide on the sun, which are not usually measurable in practice. Various types of them have been detected and studied during the last decades, such as coronal extreme-ultraviolet (EUV) waves (e.g., Thompson et al 1998Thompson et al , 1999Liu et al 2010;Warmuth 2010;Warmuth & Mann 2011;Yuan & Nakariakov 2012;Yang et al 2013;Liu & Ofman 2014;Muhr et al 2014;Warmuth 2015;Goddard et al 2016;Kumar et al 2017;Pascoe et al 2017;Shen et al 2018b;Cheng et al 2018;Shen et al 2019;Goddard et al 2019;Pascoe et al 2019), chromospheric Moreton waves (Moreton 1960;Krause et al 2018;Chen & Wu 2011), fast mode (Ofman & Thompson 2002;Liu et al 2011Liu et al , 2012Yuan et al 2013;Zhang et al 2015;Ofman & Liu 2018) and slow mode (e.g., Nakariakov & Zimovets 2011;Yuan et al 2015b) magnetosonic waves. There are various types of waves that can lead to coronal loop and filament oscillations (Nakariakov & Ofman 2001;Nakariakov & Verwichte 2005;Chen et al 2008;Liu et al 2012;Shen et al 2014a,b;Zhou et al 2018).…”

Section: Introductionmentioning

confidence: 99%

Two Quasi-periodic Fast-propagating Magnetosonic Wave Events Observed in Active Region NOAA 11167

Miao

Liu

Elmhamdi

et al. 2020

ApJ

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We report a detailed observational study of two quasi-periodic fast-propagating (QFP) magnetosonic wave events occurred on 2011 March 09 and 10, respectively. Interestingly, both the two events have two wave trains (WTs): one main and strong (WT-1) whereas the second appears small and weak (WT-2). Peculiar and common characteristics of the two events are observed, namely: 1) the two QFP waves are accompanied with brightenings during the whole stage of the eruptions; 2) both the two main wave trains are nearly propagating along the same direction; 3) EUV waves are found to be associated with the two events. Investigating various aspects of the target events, we argue that: 1) the second event is accompanied with a flux rope eruption during the whole stage; 2) the second event eruption produces a new filament-like (FL) dark feature; 3) the ripples of the two WT-2 QFP waves seem to result from different triggering mechanisms. Based on the obtained observational results, we propose that the funnel-like coronal loop system is indeed playing an important role in the two WT-1 QFP waves. The development of the second WT-2 QFP wave can be explained as due to the dispersion of the main EUV front. The co-existence of the two events offer thereby a significant opportunity to reveal what driving mechanisms and structures are tightly related to the waves.

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Dispersive Evolution of Nonlinear Fast Magnetoacoustic Wave Trains

Cited by 21 publications

References 50 publications

Fast magnetoacoustic wave trains with time-dependent drivers

Fast magnetoacoustic wave trains with time-dependent drivers

Fast magnetoacoustic wave trains: from tadpoles to boomerangs

Two Quasi-periodic Fast-propagating Magnetosonic Wave Events Observed in Active Region NOAA 11167

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